If you’re looking for info on paper sizes, how they compare in the USA vs the UK, and what their measurements are then read our ultimate guide below.
Paper sizes differ depending on whether you live in the USA, Canada, the United Kingdom or Europe. This is largely due to the different systems of measurement in place, with the USA using imperial measurements (inches and feet) and most of the rest of the world using the metric system (millimetres and centimetres).
In our guide below we show different paper sizes/dimensions, and how they compare to each other.
USA Paper Sizes
View information on USA paper sizes
UK / International Paper Sizes
View information on International paper sizes
What are the UK / International Paper sizes?
There are 11 standard UK paper sizes, belonging to the A-class. Sizes start with the largest size A0 to the smallest size A10.
UK paper sizes follow the ISO 216 (International Organisation for Standardisation) size, which is the most commonly used paper size / standard across the world.
As paper sizes get smaller, you can work out the next size down by dividing the longest side by 2. For example, for an A3 sheet of paper measuring 297 mm x 420 mm, the next size down is an A4 sheet. Dividing the longest side 420 mm by 2 gives us 210 mm. An A4 sheet measures 210 mm x 297 mm.
Paper size dimensions A3 to A10
Paper size dimensions A0 and A1
UK Paper sizes chart
Paper Class
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
Size in mm
841 x 1189 mm
594 x 841 mm
420 x 594 mm
297 x 420 mm
210 x 297 mm
148.5 x 210 mm
105 x 148.5 mm
74 x 105 mm
52 x 74 mm
37 x 52 mm
26 x 37 mm
Size in cm
84.1 x 118.9 cm
59.4 x 84.1 cm
42 x 59.4 cm
29.7 x 42 cm
21 x 29.7 cm
14.85 x 21cm
10.5 x 14.85 cm
7.4 x 10.5 cm
5.2 x 7.4 cm
3.7 x 5.2 cm
2.6 x 3.7 cm
Size in inches
33.1 x 46.8 inches
23.4 x 33.1 inches
16.5 x 23.4 inches
11.7 x 16.5 inches
8.3 x 11.7 inches
5.8 x 8.3 inches
4.1 x 5.8 inches
2.9 x 4.1 inches
2.0 x 2.9 inches
1.5 x 2.0 inches
1.0 x 1.5 inches
Often used for
Technical drawings, posters.
Technical drawings, posters.
Technical drawings, posters.
Posters, presentations.
Standard printer paper.
Leaflets, diaries, books.
Postcards, photos.
Postcards, leaflets, stickers.
Business cards.
Labels.
Tickets, stamps.
What size is A3 paper?
A3 paper measures 297 mm x 420 mm
A3 is two times the size of A4 which is the standard letter-sized paper. Some printers can also print on sheets of A3 paper which is the size of a small poster.
A3 is bigger than A4, A5, A6, A7, A8, A9 and A10 but half the size of A2.
What size is A4 paper?
A4 paper measures 210 mm x 297 mm
A4 is the standard letter paper size in the UK and is widely used in printers or copier machines. It’s often purchased in ‘paper reams’. It’s the most common paper size used across the world.
Before standardisation and adoption of the metric system, the UK’s most common paper size was ‘foolscap’, which measured 8 inches x 13 inches (203 mm x 330 mm).
A4 is bigger than, A5, A6, A7, A8, A9 and A10.
What size is A5 paper?
A5 paper measures 148.5 mm x 210 mm
A5 is one size smaller than A4 If you fold a landscape A4 sheet of paper in half across the middle (folded top to bottom), it would equal an A5-sized sheet of paper. A5 is the size often used for flyers or small notepads.
A5 is bigger than A6, A7, A8, A9 and A10.
What are the US Paper sizes?
There are 4 US paper sizes that are common to the USA and Canada, belonging to the North American paper class which follows the ANSI standard (American National Standards Institute) size. As the Imperial system is used, measurements are typically stated in inches.
There are also 3 additional less common paper sizes including government letter / legal and half letter sizes.
Standard paper sizes in the USA are Letter and Legal which measure 8.5 x 11 inches and 8.5 x 14 inches respectively.
North American paper sizes and dimensions
North American paper sizes vs international
US Paper Size Chart
Paper Class
Junior Legal
Letter
Legal
Tabloid
Half Letter
Government Letter
Government Legal
Size in inches
8 x 5 inches
8.5 x 11 inches
8.5 x 14 inches
11 x 17 inches
5.5 x 8.5 inches
8 x 10 inches
8.5 x 13 inches
Size in mm
203 x 127 mm
216 x 279 mm
216 x 356 mm
279 x 432 mm
140 x 216 mm
203 x 254 mm
216 x 330 mm
Size in cm
20.3 x 12.7 cm
21.6 x 27.9 cm
21.6 x 35.6 cm
27.9 x 43.2 cm
14 x 21.6 cm
2.03 x 25.4 cm
21.6 x 33 cm
Often used for
Writing pads.
Office, Academic.
Legal pads, contracts.
News papers.
Flyers, greetings cards.
Not commonly used.
Not commonly used.
Paper Size Questions & Answers
What size is standard Printer Paper?
Standard printer paper size in the USA is Letter – 8.5 x 14 inches (216 x 279 mm)
Standard printer paper size in the UK is A4 – 210 x 297 mm (8.3 x 11.7 inches)
Why do paper sizes differ in the USA and UK / internationally?
US and UK / international paper sizes that are most commonly used in their respective countries differ for the following reasons:
- Different systems of measurement.
- History & independence.
- Design, mathematics & Industry.
Systems of measurement
The US uses the imperial system (inches) and the UK uses the metric system (millimetres and centimetres) to measure their paper sizes. Conversions of sizes between the two systems can give odd measurements.
History & Independence
After world war 2 much of Europe had to be rebuilt and a standardised measurement system (metric) was put in place to aid that rebuild. The USA was already very independent and since international trade wasn’t what it is today. There was no need for the US to adopt the same system, plus they also wanted to maintain their own independence.
Design & Mathematics & Industry
Original paper manufacture in the US was done by hand in moulds using measurements in inches in the standard letter size, whereas international paper formats were made using the mathematical ratio of 2 to 1, folding paper in half across its width gives exactly the next size of paper down.
As the imperial system was in place in the USA during the industrial revolution, machinery was manufactured using inches. Whilst internationally the metric system was used, whenever there were government debates in the US around switching to metric, this would have been problematic and the influence of big businesses meant switching was a none starter.
What is ISO & ANSI with regards to paper?
In the US the ANSI is the American National Standards Institute that set the standards for paper sizes in North America.
In the UK / internationally, paper sizes are set by the ISO (International Organisation for Standardisation ) under rule 216.
What is the Aspect Ratio of International ISO paper?
The aspect ratio of ISO paper is the square route of 2 or 1.4142:1
If you’re looking to purchase paper here in the UK, we sell a range of office paper for your printer, as well as ink and toner cartridges.
About Stuart DeavallI have been working in the printing industry with TonerGiant for over 16 years, and I'm the resident technical printer expert, helping people fix their printer problems for over 14 years. I have taken part in many training courses with HP, Samsung, Brother, Canon and Xerox to further my knowledge, and I'm also the Digital Marketing Manager at TonerGiant.co.uk (degree qualified).
Excellent information! Well done.